Heat pumps · Error codes · Waterkotte
HP-faultWaterkotte · EcoTouch Ai1 Geo (5006.5-5013.5)
HP-fault on a Waterkotte EcoTouch Ai1 Geo: Fault at output side (HP fault)
Short answer
On a Waterkotte heat pump, HP-fault means: Fault at output side (HP fault). The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Fault at output side (HP fault).
Likely causes:
- Condenser water too cold (<20C) or quick temperature change; insufficient refrigerant (sight glass); incorrect controller parameter; sensor misaligned; inadequate water circulation or too few heating circuits open; hot water temperature too high; air in water circuit; dirt trap clogged; circulation pump defect or wrong rotation.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
- Note the code and any text shown on the display/controller.
- Check the heat pump isolator and consumer-unit breaker are on.
What the engineer will check
- Work through listed causes: Condenser water too cold (<20C) or quick temperature change; insufficient refrigerant (sight glass); incorrect controller parameter; sensor misaligned; inadequate water circulation or too few heating circuits open; hot water temperature too high; air in water circuit; dirt trap clogged; circulation pump defect or wrong rotation.
Who to ask for: heat pump engineer.
Certification: F-gas certified engineer (refrigerant circuit).
Sources
- Waterkotte EcoTouch Ai1 Geo / EcoTouch DS 5018 Ai - Planning and Installation Manual (21.11.2015, Z20469) ↗ · Z20469 · page 63 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026